Lightweight electronic device for automotive applications and method

ABSTRACT

A lightweight radio/CD player for vehicular application is virtually “fastenerless” and includes a case and frontal interface formed of polymer based material that is molded to provide details to accept audio devices such as playback mechanisms (if desired) and radio receivers, as well as the circuit boards required for electrical control and display. The case and frontal interface are of composite structure, including an insert molded electrically conductive wire mesh screen that has been pre-formed to contour with the molding operation. The wire mesh provides EMC, RFI, BCI and ESD shielding and grounding of the circuit boards via exposed wire mesh pads and adjacent ground clips. The major components and subassemblies self-interconnect by integral guide and connection features effecting “slide lock” and “snap lock” self-interconnection. The major components and subassemblies self-ground by establishing an interference fit with exposed, resilient, embossed portions of wire mesh.

RELATED APPLICATIONS

The present application is a divisional of U.S. Ser. No. 13/344,807,filed 6 Jan. 2012, entitled “LIGHTWEIGHT AUDIO SYSTEM FOR AUTOMOTIVEAPPLICATIONS AND METHOD”, which is a divisional of U.S. Ser. No.12/370,319, filed 12 Feb. 2009, entitled “LIGHTWEIGHT AUDIO SYSTEM FORAUTOMOTIVE APPLICATIONS AND METHOD”, which is a continuation-in-part ofU.S. Ser. No. 11/893,357, filed Aug. 15, 2007, entitled “LIGHTWEIGHTAUDIO SYSTEM FOR AUTOMOTIVE APPLICATIONS AND METHOD”, which claims thebenefit of U.S. Ser. No. 60/838,698 filed Aug. 18, 2006 and U.S. Ser.No. 60/931,467, filed May 23, 2007, which are assigned to a commonassignee. The instant application also claims the benefit of U.S. Ser.No. 61/066,065, filed Feb. 15, 2008, entitled ‘LIGHTWEIGHT ELECTRONICDEVICE FOR AUTOMOTIVE APPLICATIONS AND METHOD. The teaching andspecifications of the forgoing related applications are incorporatedherein by reference.

TECHNICAL FIELD

The present invention relates generally to apparatus for enclosingelectrical subassemblies, and more specifically relates to apparatus forefficiently securing subassemblies to a chassis of an electricalassembly such as an automobile radio, compact disc playing mechanism,cassette tape playing mechanism, navigational aid, personal computer,personal and telematic communication devices or disk drive mechanism.

BACKGROUND OF THE INVENTION

Devices such as automobile radios or personal computers containsubassemblies such as cassette playing mechanisms or disk drives thatare attached to the chassis using threaded fasteners. The chassisprovides structural support for the subassemblies and also provideselectromagnetic shielding to limit electromagnetic interference (EMI)experienced by, and/or created by the device. The fasteners ensure thateach subassembly within the chassis is properly located and securelyretained within the chassis.

The use of such fasteners can have numerous drawbacks, particularly in ahigh volume production setting. The process for applying or installingfasteners can vary, but there is usually some degree of automationrequired, ranging from manually loading a screw into a bit on apneumatic driver to using self-feeding automated machines. Typically,the torque applied by the device used to drive the fasteners must bemonitored regularly and adjusted in order to assure proper seating ofthe fasteners. When fasteners are used, sheet metal tolerances, as wellas tolerances of the fasteners themselves, have to be maintained attight levels to allow for the minimization of stress in the assemblywhen aligning multiple fasteners with corresponding holes in the chassisand in the subassembly.

When threaded fasteners are used to assemble an electrical device, theassembly cycle time can be very long especially in high volumeproduction. An operator assembling the device must typically firstobtain the threaded fastener, orient and position it in alignment withthe driver bit, then manipulate or actuate the machine to drive thethreaded fastener. Furthermore, using threaded fasteners presents a riskof any one of the following upstream failures occurring: stripping offastener threads; insufficient torque resulting in an unseated fastener;excessive torque resulting in distension/deformation of the fastener oradjacent electrical components; installation of the wrong fastener typeor size; foreign object damage due to fasteners and/or metal shavingsdropping onto the assembly and/or subassembly; and stripping of the headof the threaded fastener. Also, a fastener installation tool such as adriver and bit can slip off the fastener and impact an electricalcomponent resulting in a damaged assembly.

If self-tapping fasteners are used, the process of driving theself-tapping fasteners into sheet metal often causes shavings of sheetmetal to disperse into the assembly. Such shavings have been known tocause electrical failures, such as shorts or corruption of magneticcomponents that can permanently damage the product. If self-tappingfasteners are not used, an extra production step is required to pre-formthreads in the sheet metal of the chassis and/or the subassembly to beinstalled within the chassis.

Fasteners further require an additional inventory burden on theproduction line in that the production line must be continuously stockedwith part numbers (fasteners) other than the integral components thatadd value to the assembly. Also special tools specifically required forassembly, using fasteners, such as drivers and bits, must becontinuously monitored and maintained for proper performance, wear andtorque specifications. Typically, the top and/or bottom surface of thechassis must be secured in place after the subassembly is attached tothe chassis.

Special fixtures are often required on the production line to secure asubassembly in a proper location and orientation while it is mountedwithin the chassis with fasteners. Such fixtures can be very complex,and the use of such fixtures usually requires extra handling of both thesubassembly and of the resulting assembly thereby adding to theproduction cycle time and potentially compromising quality of the finalproduct.

FIG. 1 illustrates the construction of a typical prior art automotiveradio/compact disc (CD) player 10. Radio/CD player 10 comprises a radiosubassembly whose principle circuit components are carried on a circuitboard 12 and a CD player subassembly 14. The circuit board 12 and the CDplayer 14 are encased within a common chassis 16 made up of sheet metalcomponents. Chassis 16 includes a wraparound housing 18 defining a backand sidewalls, a top cover 20, a bottom cover 22 and a front plate 24which are interconnected by numerous threaded fasteners to collectivelyenclose the subassemblies. The top and bottom covers 20 and 22,respectively, are provided with large arrays holes or openings forairflow and ventilation of heat generated within the radio/CD player 10.A convector or heat sink 26 is carried on an outer surface of one of thechassis sidewalls and is interconnected through a port/window 28 to apower device assembly 30. A trim plate assembly 32, along with a supportpad 34 and CD dust cover 36 are affixed to the front plate 24, providingan operator control interface with the radio/CD player 10. Circuit board12 is electrically in-circuit with the CD player subassembly 14 throughan intermediate flex wire cable 38 and with the power device assembly 30through a jumper cable 40. Information bearing labels 42 and 44 areprovided for future reference by the operator and service technicians.The radio/CD player 10 is electrically interconnected with an antenna,power supply, speakers and other related systems of a host vehicle byrear-facing connectors 46 carried on the circuit board 12 which areregistered with openings 48 in the rear wall of wraparound housing 18.The radio/CD player 10 is mounted within a host vehicle by threadedfasteners passing through openings in mounting features 50 extendingfrom front plate 24 and a rearwardly directed mounting bushing 52 whichis threadably affixed to a stud 54 carried on the outer surface of therear wall 56 of wraparound housing 18. As best seen in FIGS. 11 and 12,the shank of the stud 54 extends outwardly through a hole 58 disposedconcentrically with a localized recess 60 and the stud 54 is seatedwithin the recess 60. FIG. 90 illustrates another known stud designincluding a threaded shank secured to the rear wall 53 of a radio set 51by a set nut 55 and receiving a molded rubber, plastic or vinyl stud 57thereover. Note the large number of threaded fasteners 59.

The radio/CD player 10 of FIG. 1 is of ordinary complexity and mayrequire fifty or more threaded fasteners to complete the manufacturingprocess. Installation of that many fasteners may require that thein-process chassis be re-positioned/re-fixtured ten to fifteen times asit passes along an assembly line of eight to ten skilled workers/workstations.

Vehicle entertainment systems usually include an audio component such asa radio to enable receiving signals from antennas, contain various formsof playback mechanisms, and have the capacity to accept data from userdevices like MP3 players. Typically, the radio has a decorative assemblythat provides man-machine interface as well as displaying pertinent datarelative to the selected media and audio settings. Also, the back-end orchassis is constructed of metal to provide various functions to ensurethe performance of the radio in the vehicular environment. The structureto contain the mass from playbacks, the heat conductive properties, andthe electrical shielding and grounding are just a few of the advantagesto using the metal construction. Unfortunately, with the density of themetal, the disadvantage of added weight is a side effect of the typicalconstruction. In a vehicle, added weight impacts fuel economy, as wellas other hidden costs during assembly that can effect the cost of theproduct, like sharp edges of metal can be a potential hazard forassemblers in the manufacturing plant as well as added weight can limitthe packaging of multiple parts in containers for inter and outer plantdistribution.

Special fixturing is often required to hold a component in the properlocation while it is mounted to the convector using one or morefasteners. Such fixturing can be very complex and use of such fixturingusually requires extra handling of both the component and of theresulting assembly, thereby adding to the production cycle time andpotentially compromising quality of the final product.

When threaded fasteners are used, the assembly cycle time can be verylong, especially in high volume production. The operator mustspecifically obtain the threaded fastener, bring it in contact with thedriver bit, then drive the threaded fastened. If self-tapping fastenersare used, the process of driving the self-tapping fasteners into metaloften causes metal shavings to disperse into the assembly. Such shavingshave been known to cause electrical failures that can permanently damagethe product. If self-tapping fasteners are not used, an extra productionstep is necessary to form threads in the metal of the convector.

Accordingly, there is a need for electrical assemblies that do notrequire fasteners or tooling for securing a component to a convector.

SUMMARY OF THE INVENTION

The present invention provides numerous product and process advantageswhich collectively result in substantial cost and labor savings. By wayof example, the preferred design optimizes the assembly process. Itminimizes the required handling of major components and subassembliesduring the assembly cycle. Final assembly is optimized, wherein onlyseven major components and subassemblies are involved. This minimizesthe number of work stations and fixtures, in-process transfers betweenwork stations and total assembly cycle time. The inventive designpermits selection of the optimal mechanical product configuration for agiven receiver family. Furthermore, it permits idealized electrical andmechanical building block partitioning for common and unique elements.

The preferred embodiment of the invention contemplates screwless finalassembly without the use of tools, fixtures and assembly machines. Thisgreatly enhances in-process product flow in the factory, improvesscheduling of final assembly, and allows labor intensive processes suchas stick lead assembly to be largely moved off-line. This greatlyreduces both direct and indirect labor requirements. Furthermore,inventory control is simplified inasmuch as position part proliferationis deferred to or near the end of process.

These and other features and advantages of this invention will becomeapparent upon reading the following specification, which, along with thedrawings, describes preferred and alternative embodiments of theinvention in detail.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example, withreference to the accompanying drawings, in which:

FIG. 1, is an exploded, perspective view of a prior art automotiveradio/CD player combination in a common chassis constructed of sheetmetal and a large number of threaded fasteners;

FIG. 2, is a front-left perspective view of the preferred embodiment ofthe present invention embodied in an automotive radio/CD player;

FIG. 3, is an exploded, perspective view of the radio/CD player of FIG.2, illustrating the major subcomponents and subassemblies thereof;

FIG. 4, is an exploded, perspective view of the radio/CD player of FIG.2, illustrating final assembly step I in the production thereof whereinthe playback mechanism and circuit board assembly are slid and snappedto the faceplate;

FIG. 5, is an exploded, perspective view of the radio/CD player of FIG.2, illustrating final assembly step II in the production thereof whereinthe case is slid and snapped to the faceplate;

FIG. 6, is a perspective view of the circuit board assembly with groundclips installed thereon;

FIG. 7, is a fragmentary, cross-sectional view of a ground clip and anassociated portion of the printed circuit board on an enlarged scale inassembly with an adjacent portion of the case to effect a groundingpoint with the integral wire mesh;

FIG. 8, is a fragmentary, perspective view of a keypad grounding clipintegrally formed on the front side of the faceplate;

FIG. 9, is a cross-sectional view taken on lines 9-9 of FIG. 8;

FIG. 10, is a cross-sectional view taken on lines 10-10 of FIG. 8;

FIG. 11, is a cross-sectional view taken on lines 11-11 of FIG. 8;

FIG. 12, is a fragmentary, cross-sectional view of the initialpositioning of a CD mechanism bracket with respect to a support shelfintegrally formed within the case;

FIG. 13, is a fragmentary, cross-sectional view of the CD mechanism inan intermediate position with respect to the support shelf during itsinstallation;

FIG. 14, is a fragmentary, cross-sectional view of the CD mechanism inits final installed position with respect to its associated supportshelf;

FIG. 15, is a fragmentary detail, on an enlarged scale, of the rear endportion retention tab of the CD mechanism bracket depicted in FIGS.12-14;

FIG. 16, is a cross-sectional view of a first portion of the retentiontab of the CD mechanism bracket taken on lines 16-16 of FIG. 15illustrating an integral dimply/crush rib formed therein;

FIG. 17, is a cross-sectional view of another portion of the retentiontab of the CD mechanism bracket taken on lines 17-17 of FIG. 15;

FIG. 18, is an end plan view of the retention tab of the CD mechanismbracket in its assembled position within the rear wall portion of thecase of the radio/CD player as depicted in FIG. 14;

FIG. 19, is a cross-sectional view of an alternative, lighter weightouter case configuration in representative assembly with a bifurcated PCboard wherein wire screen mesh provides both electromagnetic shieldingas well as a significant portion of the overall structural strength ofthe case;

FIG. 20, is a front perspective view of the interior surface details ofthe case/back-end illustrating the wire mesh screen which has beeninsert molded within the case adjacent the inner surface portionsthereof;

FIG. 21, is a front-above perspective view of a partially assembledradio/CD player, substantially similar to that previously depicted(prior to installation of the trim plate assembly), illustrating, interalia, (1) three outwardly directed spring contacts carried by resilientmembers integrally formed with the faceplate and (2) the juxtapositionof the wire mesh within the faceplate adjacent the outer surfacethereof;

FIG. 22, is a front-left perspective view of the partially assembledradio/CD player of FIG. 21, illustrating the same features from adifferent perspective;

FIG. 23, is a broken, bottom-rear perspective view of an audio systemassembly embodying an alternative embodiment of the present inventionillustrating internal PCB front and rear edge self-grounding withintegral features of the audio system housing assembly;

FIG. 24, is a broken, cross-sectional view, on an enlarged scale, of therear edge of the PCB of FIG. 23 self-engaging and self-grounding withexposed electrically conductive shield and guide tangs integrally formedwith the audio system housing assembly;

FIG. 25, is a broken, cross-sectional view, on an enlarged scale, of thefront edge of the PCB of FIG. 23 self-engaging and self grounding withexposed electrically conductive shield and guide tangs integrally formedwith the audio system housing assembly;

FIG. 26, is a broken, rear facing perspective view of the exposedelectrically conductive shield and guide tangs of FIG. 24, with the PCBremoved;

FIG. 27, is a broken, forward facing perspective view of the exposedelectrically conductive shield and guide tangs of FIG. 25, with the PCBremoved;

FIG. 28, is a cross-sectional view taken on lines 28-28 of FIG. 13,illustrating the juxtaposition of an associated pair of guideways formedby a housing case and guide members formed by a CD changer mountingbracket with the bracket partially installed within the case;

FIG. 29, is a cross-sectional view taken on lines 29-29 of FIG. 14,illustrating the juxtaposition of the associated pair of guideways andguide members with the bracket fully installed within the case;

FIG. 30, is a cross-sectional view of an alternative configuration ofthe guideways/guide members of FIGS. 28 and 29, with the respectivecontacting surfaces angularly converging;

FIG. 31, is a cross-sectional view of a second alternative configurationof the guideways/guide members of FIGS. 28 and 29, with the respectivecontacting surfaces diverging and an electrical grounding connectionestablished therebetween;

FIG. 32, is a fragmentary, cross-sectional view of the initialpositioning of a CD mechanism bracket with respect to an alternativesupport shelf integrally formed within the case, similar to FIG. 12,with the wall surfaces defining the guideways each tapered on theirupper and lower surfaces to provide a drafted condition to enhanceinjection molding formation of the case;

FIG. 33, is an exploded, left-rear perspective view of another featureof the present invention embodied in a lightweight electronic deviceconfigured for automotive applications featuring selectively embossedsegments of exposed composite case electrical shielding materialoperative to enhance screwless assembly of subassembly brackets within(or exterior of) the case;

FIG. 34, is a fragmentary, exploded, top cross-sectional view of theexemplary automotive audio system composite case of FIG. 33, juxtaposedfor installation of a cooperating pair of (CD player) subassemblymounting brackets therein, prior to contact between the bracket andcase;

FIG. 35, is a fragmentary, exploded, cross-sectional view of a portionof the case and one of the mounting brackets of FIG. 34 on an enlargedscale;

FIG. 36, is a fragmentary, exploded, top cross-sectional view of theexemplary automotive audio system composite case of FIG. 33, juxtaposedfor installation of a cooperating pair of (CD player) subassemblymounting brackets therein, at a point of initial contact between thebracket and case;

FIG. 37, is a fragmentary, exploded, cross-sectional view of a portionof the case and one of the mounting brackets of FIG. 36 on an enlargedscale;

FIG. 38, is a fragmentary, exploded, top cross-sectional view of theexemplary automotive audio system composite case of FIG. 33, juxtaposedfor installation of a cooperating pair of (CD player) subassemblymounting brackets therein, at a point of contact between the bracket andcase affecting maximum lateral displacement of integral case mountingtabs, prior to their locking engagement with a mounting feature of theadjacent subassembly mounting bracket illustrating the momentarydistention of the upset bead finned in the exposed conductive material(screen mesh);

FIG. 39, is a fragmentary, exploded, cross-sectional view of a portionof the case and one of the mounting brackets of FIG. 38 on an enlargedscale;

FIG. 40, is a fragmentary, exploded, top cross-sectional view of theexemplary automotive audio system composite case of FIG. 33, juxtaposedfor installation of a cooperating pair of (CD player) subassemblymounting brackets therein, wherein the bracket and case are fullyassembled and the integral case mounting tabs have resiliently returnedto their nominal rest positions affecting locking engagement with amounting feature of the adjacent subassembly mounting bracket;

FIG. 41, is a fragmentary, exploded, cross-sectional view of a portionof the case and one of the mounting brackets of FIG. 40 on an enlargedscale;

FIG. 42, is a fragmentary, cross-sectional view of the fully assembledautomotive electronic device and subassembly mounting bracket of FIG. 33on an enlarged scale, taken on line 42-42 of FIG. 41;

FIG. 43, is a fragmentary plan view of a portion of a composite casewall illustrating a window opening in the polymer based materialexposing conductive material (conductive screen mesh) with multipleconcentric upset beads formed therein circumscribing a discrete segmentof polymer based material (island);

FIG. 44, is a fragmentary, cross-sectional view of the case windowopening, taken on line 44-44 of FIG. 43;

FIG. 45, is a fragmentary plan view of a portion of a composite casewall illustrating a window opening in the polymer based materialexposing conductive material (conductive screen mesh) with multipleconcentric upset beads formed therein similar to FIG. 43, but lacking adiscrete segment of polymer based material (island);

FIG. 46, is a fragmentary, cross-sectional view of the case windowopening, taken on line 46-46 of FIG. 45;

FIG. 47, is a perspective view of a solid model of a male die portion ofa die set configured to affect formation of the composite electronicdevice case of FIG. 33, illustrating the detail of the region of the dieportion which establishes the case side window and affects formation ofthe conductive material upset bead upon closure with a mating dieportion (not illustrated);

FIG. 48, is a exemplary dimensioned profile of the male die portion ofFIG. 47 through its region which forms the case window; and

FIG. 49, is a Product Data Sheet of steel mesh employed by the applicantin certain embodiments of the composite case of the present invention.

Although the drawings represent varied embodiments and features of thepresent invention, the drawings are not necessarily to scale and certainfeatures may be exaggerated in order to illustrate and explain thepresent invention. The exemplification set forth herein illustratesseveral aspects of the invention, in one form, and such exemplificationis not to be construed as limiting the scope of the invention in anymanner.

DESCRIPTION OF THE ILLUSTRATIVE EMBODIMENTS

The present invention can be applied in its broadest sense to electronicdevices and systems where shielding from radio frequency interference(RH), electromagnetic interference (EMI), bulk current injection (BCI)and/or electrostatic discharge (ESD) is required. In addition to vehiclebased radios and audio entertainment systems, the invention can beadvantageously applied in “infotainment” and telematic systems.Furthermore, the present invention employs virtually “fastenerless”design architecture to facilitate low-cost, high volume productiontechniques.

For convenience of understanding, the following description will befocused primarily upon an automotive radio/CD player system.

The present invention reflects an improved design to reduce the overallweight of an automotive radio/CD player without compromising thestrength of the unit. The present invention employs a polymer based,electrically insulative material that can be molded to provide thenecessary features for the chassis as well as the frontal interface tothe decorative front-end assembly described for the man-machineinterface. By molding a case with the necessary details to accept theplayback mechanisms (if desired) as well as the circuit board(s) neededfor the electrical control, the required functionality of the unit ismaintained as compared to the typical metal box. The necessary shieldingand grounding is accomplished by insert-molding electrically conductivesheet-like material such as a mesh screen wire that has been pre-formedto contour with the molding operation. The grounding of the circuitboards may be accomplished by using ground clips attached directly tothe ground pads of the circuit board that would interface directly withexposed screen wire mesh of the molded part. While metal is also a goodconductor for the thermal load inside the unit, openings must beincorporated to allow airflow for additional cooling. The same openingscan compromise the shielding. With in-molded mesh screen wire, the meshacts as a Faraday cage to shield the electronics, but the open weaveallows airflow to promote the dissipation of the thermal load frominside the unit, to the exterior. Besides the reduction of mass offeredby the molded polymer material for the unit chassis and front plate, thehidden benefits include ease of handling in the assembly process as wellas less container and shipping weight.

To facilitate assembly, the molded polymer chassis and front plate canuse integral or molded in guideways and snaps, thereby eliminating thetypical screw fastener assembly method previously used for thesecomponents. To enhance the rigidity, the component parts that comprisethe assembly are sandwiched at the common vehicle instrument panelattachment points such that when the mounting screws are driven, theyfirmly clamp the component pieces to the host vehicle. In the event aplayback mechanism of substantial mass and volume is required, thesub-assembly structure for the mechanism would utilize formed attachmenttabs that would be an intermediate layer in the aforementioned componentpart sandwich. Another benefit for the mounting at the back of the radiois often vehicles have a receptive hole or slot in the inner cavity ofthe instrument panel carrier that accepts a mounting bushing or “bullet”shaped extension that is screwed to a mounting stud that is typicallyswaged to the back of the metal enclosure of the radio. The mounting“bullet” can be molded directly in the polymer-based case eliminatingthe additional part and the assembly of that additional part.

To replace the metal structure of the vehicle radio, a galvanized (orappropriately coated) steel mesh wire screen will be cut, formed, andmolded with a polymer resin to provide necessary details for assembly ofcomponents required for the functionality of the radio including, butnot limited to, a circuit board assembly, a heat sink for audio powerand switching components, a playback mechanism, and a man-machineinterface or trim plate assembly, as well as vehicle mounting features.While the polymer or plastic provides the majority of the mechanicalstructure for the radio, the in-molded mesh screen wire provides theneeded protection from various electrical anomalies includingelectromagnetic contamination, radio frequency interference, bulkcurrent injection, and electrostatic discharge, to name a few. Thescreen mesh also allows openings necessary for air passage or venting ofheat from the radio by molding the radio back end or case and frontplate. The many details and features needed in a typical assembly can beincorporated directly into the parts, eliminating the need for fastenersand separate additional parts often required with parts fabricated inmetal.

The specific materials selected for fabricating the radio case and frontplate will vary depending upon the application, including the containedmass of the mechanisms employed as well as the severity of thecontemplated environment (esp. temperature and vibration). Examples ofmaterials that could be employed for typical automotive applicationsare:

Case: Glass-filled polyester, Glass-filled polypropylene, Polycarbonate,ABS.

Front Plate: Polycarbonate, ABS, PC/ABS and Noryl.

Major components which contact one another or are mechanicallyinterconnected preferably are formed from material having substantiallydiffering surface finish and hardness characteristics to minimize thepossibility of resulting squeaks, rattles and the like.

Although presently viewed as cost prohibitive for automotiveapplications, it is contemplated that nano carbon tube filler can beemployed within the plastic material forming the case and front plate toprovide effective shielding and enhance the structural strength of thecase assembly.

In addition to weight savings, which may amount to well over one pound(0.4536 Kg), the part handling is improved to reduce the amount offasteners as well as separate component parts. Often a radio may beconstructed from a wrap-around, a cover and the fasteners along with amounting bushing or “bullet” screwed to a “swaged” threaded stud in themetal case. Also, the metal pieces require assembly personnel to weargloves during handling to avoid any cuts or damage to their hands aswell as protection from any metal fabrication fluid residue. Moldedplastic does not require any special gloves, or the concerns of cuts tothe skin. Aside to the benefit to the vehicle by reducing the radioweight by over one pound (0.4536 Kg), the savings for a manufacturerinclude reduced shipping cost through the weight reduction and potentialcontainer efficiency improvements. Product labeling can be improvedthrough laser engraving the plastic with the desired number, customerlogos, etc. Metal typically requires a stamping detail (not easilychanged) and/or a printed label that is adhesively applied. This offersgreater flexibility and eliminates additional parts (like labels) to usethe plastic, as well as better durability than a label.

Referring to FIGS. 2-5, a consolidated radio/CD player apparatus 62embodying many aspects of the present invention is illustrated. Theradio/CD player 62 is an assemblage of six major components orsubassemblies, a circuit board subassembly 64, a CD player subassembly66, a box-like housing case 68, a front closure member or front plate70, a convector or heat sink 72 and a trim plate subassembly 74.

It is envisioned that each of the major components/subassemblies wouldbe produced “off-line” and the final assembly process would comprise theefficient, high volume joining of the major components/subassemblies andend-of-line testing of the completed units.

FIG. 2 depicts a perspective view of the fully assembled radio/CD playerapparatus 62. FIG. 3 is an exploded view illustrating the juxtapositionof the respective major components during the assembly process. FIGS. 4and 5 depict specific assembly steps of the major components as will bedescribed hereinbelow.

The case 68 and front plate 70 are each preferably injection molded ofpolymer based material and collectively comprise a substantially closedhousing assembly 76. The case 68 has a box-like structure, includingupper and lower wall portions 78 and 80, respectively, left and rightside wall portions 82 and 84, respectively, and a rear wall portion 86.The case 68 also has mounting features extending externally of the casewalls, including left and right front mounting flanges 88 and 90,respectively, extending from the forward edges of the left and rightside walls 82 and 84, respectively, and a mounting stud 92 extendingrearwardly from the rear wall 86. All of the case wall portions andmounting features of the case 68 are integrally formed in a singleinjection molding process. The case defines a front opening 94 which,upon assembly, is closed by front plate 70. An assembly axis 96 extendssymmetrically from front to rear of the case 68, exiting opening 94along the nominal centerline of the case 96.

The circuit board subassembly 64 consists of a common or main printedcircuit board (PCB) 98 and a unique, application specific PCB 100 whichare electrically and mechanically interconnected by several pinconnectors 102. It is envisioned that edge connectors, ribbon connectorsor the like could be substituted for the pin connectors 102. The commonPCB 98 contains all surface mount components. The circuit boardsubassembly 64 comprises an audio component.

The CD player subassembly 66 consists of a conventional multi-discplayer unit 104 and substantially minor-image left and right sidemounting brackets 106 and 108, respectively, affixed thereto by integralfastener devices such as “squirts”. Note that there are slightdifferences between the left and right mounting brackets 106 and 108,but they are deemed to be inconsequential for purposes of the presentinvention. The left and right mounting brackets 106 and 108 haveoutwardly directed mounting flanges 110 and 112, respectively, which,upon assembly, register with case mounting flanges 88 and 90,respectively. The CD player subassembly 66 comprises an audio component.

The heat sink 72 comprises a substantially flat, stamped aluminum plateadapted for mounting to the outer surface of the left case sidewall 82and includes a recessed portion 114 which, upon installation, extendsinwardly through a port 116 in left case sidewall 82 for thermalinterconnection to heat generating and power circuit components 118, 120and 122 carried on the main PCB 98.

The trim plate subassembly 74 is configured to organize audio systeminput/output and display devices, informational indicia and decorativedisplay devices for an associated host vehicle operator.

Referring particularly to FIGS. 4 and 5, a method of assembly of thelightweight audio system 62 of the present invention is illustrated.Audio system 62 can be assembled manually by an ordered process whereina single (preferably, but not limited to) operator, who sequentiallyassembles the six major components or subassemblies on a designated worksurface 124. No specialized tools or separate/dedicated fixtures arerequired. No threaded fasteners/screws are required. Each or the majorcomponents and subassemblies form integral features which cooperate tointeract with features of the other components and subassemblies toregister, align and guide the components and subassemblies duringadjoining thereof as well as to removably affix the components andsubassemblies to one another when in their final design position. Thisprocess is referred to herein as the Slide-lock Snap-lock™ ScrewlessAssembly Technology and Method or “SLAT”. In effect, the components“self-fixture one another in combination the manipulation of the

Assembly of the radio/CD player 62 is affected by the assemblytechnician or operator taking the following steps:

As illustrated in FIG. 4, place the front plate 70 on the work surface124 in an inverted position with the outer surface of the front platedisposed upon the work surface 124. The centerline of the front plate 70defines an assembly axis, as designated by arrow 96 extending normallyto the work surface 124.

The front plate has two laterally spaced, rearwardly directed extensions126 and 128 integrally formed therewith. Extensions 126 and 128 formguideways or opposed slots 130 and 132, respectively, which open towardsone another and are directed parallel to the assembly axis 96. Lateraledge guide surfaces 134 and 136 of the application specific PCB 100register within slots 130 and 132 and are guided thereby during theinsertion process until the leading edge surface 138 of the PCB 100contacts the inside (upward facing in FIGS. 4 and 5) surface of frontplate 70. At this point, common PCB 98 is cantilever suspended from PCB100 via pin connectors 102 and other supports (not illustrated).Referring FIG. 5, the circuit board subassembly 64 is retained inposition by the interfit of the edge surfaces 134 and 136 within slots130 and 132.

The CD player subassembly 66 is next installed by manipulating it alongthe assembly axis 96 until through holes 140 and 142, formed in bracketmounting flanges 110 and 112, register with locating pins or nibs 144and 146 integrally formed in laterally extending mounting flanges 148and 150, respectively, integrally formed in front plate 70. Thereafter,the CD player subassembly is displaced downwardly along the assemblyaxis 96 until the lower surfaces of bracket mounting flanges 110 and 112abut the upper surfaces of front plate mounting flanges 148 and 150. TheCD player subassembly 66 is retained in the position illustrated in FIG.5 by an interference fit between the front plate nibs 144 and 146, andthe mounting bracket flange through holes 140 and 142.

Mounting bracket flanges 110 and 112 have secondary, larger diameterthrough holes 152 and 154 formed therein which register with similarlydimensioned through holes 156 and 158, respectively, formed in frontplate mounting flanges 148 and 150 for receiving attachment means suchas bolts, for affixing the completely assembled radio/CD player 62 to ahost vehicle.

The steps of installing the circuit board subassembly 64 and the CDplayer subassembly can be reversed from that describer hereinabove.

The housing case 68 is next installed by manipulating it along theassembly axis 96 whereby the case wall portions 78, 80, 82, 84 and 86fully envelop the circuit board subassembly 64 and CD player subassembly66 in combination with the front plate 70.

As best viewed in FIGS. 3, 5 and 20, the centerline of the case 68 isfirst manually aligned with the assembly axis 96 and rotationallypositioned with the subassembly consisting of the circuit boardsubassembly 64, CD player subassembly 66 and the front plate 70, wherebya first cooperating pair of guideways 160 and 162 integrally formed incase sidewall portions 82 and 84 register with the CD player mountingbrackets 106 and 108 and, simultaneously, a second cooperating pair ofguideways 164 and 166 integrally formed in case sidewall portions 82 and84 register with lateral edge guide surfaces 168 and 170 of common PCB98. The case 68 is then manually displaced along the assembly axis 96until the leading edge thereof defining front opening 94 contacts therear surface of the front plate 70. Thereafter, cooperating rampedsnap-engagement features 172 and 174 integrally formed with upper andlower wall portions 78 and 80 of the case 68 and the front plate 70,respectively, momentarily self-displace one another and snap back toself-engage to establish a positive interlock therebetween.

The case mounting flanges 88 and 90 form through holes 176 and 178 whichregister and self-engage with nibs 144 and 146, respectively, to providea redundant engagement feature. Furthermore, the case mounting flanges88 and 90 form a second set of through holes 180 and 182, respectively,which register with through holes 152 and 154 of mounting brackets 106and 108, and through holes 152 and 154 of front plate mounting flanges148 and 150, respectively.

As best viewed in FIG. 2, the heat sink 72 is next installed. The heatsink 72 includes several locating tabs 182 integrally formed along oneedge thereof and a locator recess 184 formed in an opposed edge. Theheat sink 72 is manually affixed to the outer surface of the case leftside wall portion 82 which defines integral tab receiving extensions 186along the upper edge thereof. Once the heat sink locating tabs 182 areinserted within their respective case wall portion extensions 186, theheat sink 72 is rotated into its design position wherein a resilientramped catch member 188 integrally formed along the bottom edge of theleft side wall portion 82 snap engages the recess 184 to fixedlyinterlock the heat sink 72 to the case 68.

When the heat sink 72 is in its installed position, the recessed portion114 extends inwardly into the case 68 through the port 116. The innersurface of the recessed portion 114 establishing an abuttingrelationship against the power circuit components 118, 120 and 122 toprovide a cooling thermal convector to the exterior of the case 68.Means are provided to ensure that components 118, 120 and 122 remain inintimate contact with the heat sink 72 such as screws 190, or,preferably to continuously resiliently urge the components intoengagement with the recessed portion 114 of the heat sink 72.

It is contemplated that the heat sink 72 could be alternatively mountedto the case rear wall portion 86, whereby it would be installed alongthe assembly axis 96.

As a final step of assembling the major components and subassemblies,the subassembly of the components is manually inverted, with the caserear wall portion 86 disposed on the designated work surface 124. Due tothe localized outward projection of the stud 92, a stability enhancingspacer (not illustrated) or, alternatively, a recess 192 in the worksurface 124 ensures a stable platform to complete assembly.

The trim plate subassembly 74 is then manipulated to become in registerwith the case 68 and manually displaced along the assembly axis 96 untilthe lower surface of the trim plate assembly 74 contacts the uppersurface of the front plate 70. Thereafter, cooperating rampedsnap-action engagement features 192 and 194 integrally formed with upperand lower edge skirt surfaces of the case trim plate assembly 74 and thefront plate 70, respectively, momentarily self-displace one another andsnap back to self-engage to establish a positive interlock therebetween.

The completed assembly of the major components and subassemblies isdepicted in FIG. 2. Following the assembly process, the completedradio/CD player 62 is placed in a queue for testing and quality checks.

The rear mounting bushing for current radios is typically attached bywelding a threaded stud to the back wall of the wrap around and then thebushing is screwed on. With the plastic box receiver, the mountingbushing can be molded as an integral part of the receiver box,eliminating two part numbers and the labor to install them.

FIGS. 20-22 illustrate an alternative construction of the case 68 andfront plate 70 of the housing assembly 76 wherein both elements of thecase assembly 76 are formed of a composite of relatively rigid polymermaterial and electrically conductive material operable to shield theaudio components (such as the circuit board subassembly 64 and the CDplayer subassembly 66) from electrical anomalies including radiofrequency interference (RFI), electromagnetic interference (EMI), bulkcurrent injection (BCI) and electrostatic discharge (ESD). Theelectrically conductive material comprises substantially continuousplaner sheet portions applied to surfaces of or within polymer housingassembly wall portions as discrete elements, electrically conductivepaint, foil or electrostatic or vacuum deposition applied material.Alternatively, the electrically conductive material comprises a wiremesh screen 212 which has been cut and folded to net shape and insertedwithin a mold cavity whereby it is effectively insert molded within thepolymer based material. Preferably, the wire screen 212 is centeredwithin the wall portions of the case and front plate wherebyelectrically insulating polymer material effectively covers the wirescreen 212, both inside and out, to prevent inadvertent grounding of thehousing assembly to interior or exterior structures.

Through empirical testing and development, the inventors have found thatit is preferable to locate the wire screen 212 near the inside surfaceof the case 68 and the outside surface of the front plate 70. Openings214 are provided in the case 68 by locally eliminating the polymermaterial but leaving the wire screen intact, whereby judiciouslypositioned openings 214 provide natural convection cooling to theambient without having a break or gap in the electrical anomalyprotection provided by the wire screen 212.

The common circuit board and the unique circuit board are grounded tothe molded in wire mesh by using a grounding clip that contacts theground plane on the circuit board to the metal mesh by pressing thecircuit board with the clip installed into a hole or recess in theplastic box that exposes the mesh. A point/ridge/protuberance is used onthe clip to press into the mesh and increase the pressure for intimatecontact. An alternative of this clip is one that gets surface mountedand soldered to the board and does not require manual assembly.

Referring to FIGS. 6 and 7, one form of grounding the ground plane 216of the circuit board subassembly 64 to the wire screen 212 isillustrated. The leading edge surface 138 of the unique PCB 100 carriestwo beryllium copper grounding clips 218, which are electrically andmechanically connected to the PCB ground plane 216. Similarly, atrailing edge surface 222 of the common PCB 98 carries two groundingclips 218. Each grounding clip 218 includes a resilient contact arm 220extending outwardly along the assembly axis 96. Upon assembly, thegrounding clips 218 carried on the leading edge surface 138 of PCB 100register with exposed wire screen 212 within windows 224 in front plate70 (refer FIGS. 21 and 22), and the grounding clips 218 carried on thetrailing edge surface 222 of PCB 98 register with exposed wire screen212 within windows 226 in the rear wall portion 86 of the case 68. Thecontact are 220 of each grounding clip 218 is configured to continuouslybear against the adjacent exposed wire screen 212 to maintain electricalcontact therewith.

Referring to FIGS. 23-27, alternative forms of grounding the groundplane 216 of the circuit board subassembly 64 to the wire screen areillustrated. FIG. 23 illustrates a radio/CD player 622 similar in allmaterial respects to the radio/CD player 62 described hereinabove inconnection with FIGS. 2-11 inter alia, with the exceptions describedimmediately hereinbelow. In essence, in this embodiment, the four groundclips 218 contained on the circuit board subassembly 64 are deleted andreplaced by connectors integrally formed with the housing assembly 76.

Referring to FIGS. 23, 25 and 27, a circuit board subassembly 624includes a common PCB 626 interconnected with a unique PCB 628 by pinconnectors 630. A leading edge 631 of the unique PCB 628, when installedwithin a front plate 632, engages two Z-clips 634 integrally formedwithin the front plate 632, whereby wire screen 636 exposed in theZ-clip 634 engages a contact pad/plane 638 carried on the unique PCB 628adjacent its leading edge 631. A trailing edge 652 of the common PCB626, when installed in a housing case 654, engages two grounding clips658 integrally formed within the case 654, whereby wire screen 636exposed in the grounding clip 656 engages a contact pad/plane 658carried on the common PCB 626 adjacent its trailing edge 652.

As best viewed in FIGS. 25 and 27, the Z-clip 634 includes a frame 640integrally formed adjacent one side of an associated opening 642 andextending inwardly (within an associated housing case 643) therefrom asa resilient cantilever. The frame 640 includes two parallel “L’ or “J”shaped leg portions 644 interconnected by a cross support portion 646. Aflap of wire screen 636 is die-cut prior to being injection moldedwithin the front plate 632. During the injection molding process, theedges of the wire screen flap are insert molded within the leg portions644, the cross-support portion 646 and the adjacent front panel of thefront plate 632, thereby exposing the wire screen flap 636 forelectrical connection with the unique PCB contact pad 638. An inwardlydirected boss 648 is integrally formed on the front plate 632 adjacentan edge of the opening 642 opposite from the leg portions 644, andextends substantially parallel to an assembly axis 649. The boss 648forms a guide/abutment surface 650 which is spaced from the exposed wirescreen flap 636 by a dimension slightly less than the thickness of theunique PCB 628 to ensure a tight compressive fit when the leading edge631 of the unique PCB 628 is inserted therebetween. The naturalresiliency of the polymer material forming the Z-clip frame 640 ensurescontinued continuity of the electrical connection between the exposedwire screen 636 of the Z-clip and the unique PCB contact pad 638.

As best viewed in FIGS. 24 and 26, the grounding clip 656 includes acooperating pair of laterally spaced support members 660 and 662integrally formed in a rear wall portion 664 of the case 654 adjacentthe bottom edge of an associated opening 663 and extending inwardlytherefrom. A flap of wire screen 666 is die-cut prior to being injectionmolded within the case 654. During the injection molding process, thelateral edges of the wire screen flap 666 are insert molded within thesupport members 660 and 662 and the adjacent portion of the case rearwall portion 664, thereby exposing the wire screen flap 666 forelectrical connection to the common PCB 626 contact pad 658. A wirescreen positioning finger 668 is integrally formed in the rear wallportion 664 of the case 654 laterally intermediate the support members660 and 662, and extends inwardly from the rear wall portion 664substantially parallel to an insertion axis 670 as a resilientcantilever. The positioning finger 668 is vertically positioned withrespect to the support members 660 and 662 to continuously contact thelower surface of the wire screen flap 666 to ensure that the lateralcenter portion of the wire screen flap 666 is bowed slightly upwardlyand resiliently maintained at least slightly above the upper surfaceportions 672 and 674 of the support members 660 and 662, respectively.An inwardly directed boss 676 is integrally formed on the rear wallportion 664 of the case 654 adjacent the top edge of the opening 663opposite from and laterally centered with the support members 660 and662. The boss 676 forms a guide/abutment surface 678 which is spacedfrom the exposed wire screen flap 666 by a dimension slightly less thanthe thickness of the common PCB 636 to ensure a tight compressive fitthen the trailing edge 652 of the common PCB 636 is insertedtherebetween. The natural resiliency of the polymer material forming theground clip 656 structural elements ensures continued continuity of theelectrical connection between the exposed wire screen 666 of the groundclip 656 and the common PCB contact pad 658.

In another example of self-grounding a PCB 680 includes an extension 682projecting forwardly therefrom in line with an assembly axis 684 of ahousing case 686 for an audio system 687. Contact pads 688 and 690 arecarried on upper and lower surfaces 692 and 694 of the PCB extension682. A rear wall portion 696 of the case 686 forms a window 698 exposinga portion of wire screen 700 which is aligned with the PCB extension682. When the wire screen 700 is insert molded within the polymericmaterial forming the case 686, the portion thereof coinciding with thewindow 698 is left intact. During the assembly process of the audiosystem 687, wherein the PCB is installed by insertion along guideways(not illustrated) within the case 686, the PCB is inserted withsufficient force to locally rupture and penetrate the exposed wirescreen 700 within the window 688. Following the rupture of the wirescreen 700, the residual separation edges thereof are drawn into thewindow 698 by friction caused by motion of the upper and lower PCBsurfaces 692 and 694, respectively. When the PCB 680 assumes itsinstalled position, as illustrated in FIG. 139, the rended portions ofthe wire screen 700 are compressively fit between the contact pads 688and 690 and the adjacent edges of the window 698, ensuring continuedcontinuity of the electrical connection between the exposed wire screen700 and the PCB contact pads 688 and 690. It is contemplated that asingle (one side of the PCB) contact pad can also be employed. However,the redundancy afforded by the dual contact pads 688 and 690 ispreferable.

In a modification of the self-grounding system described hereinabove canenhance assembly of an audio system 702 for simplified and improvedunit-to-unit repeatability. A housing case 704 includes a wall portion706 forming a window 708 exposing a wire screen 710 to establish a pointof electrical connection to an audio component within the case 704.After the wire screen 710 is insert molded within the polymer materialforming the case 704, but before the assembly if the audio system 702, atool, such as a cooperating punch 712 and die 714 is pressedsimultaneously against the inner and outer surfaces of the exposedscreen 710 within the window 708 to form perforations or weakenings,indicated by dotted lines 716. This process step is indicated by arrows718. The perforations 716 make the exposed wire screen 710 morepredictably frangible for improved unit-to-unit quality. Thereafter,during final assembly of the audio system 702, the wire screen 710separates along the perforations 716 when contacted by the leading edgeof a PCB extension 682.

An alternative self grounding approach involves modifying a leadingsurface 720 of an extension 722 of a PCB 724 to form a sharpened,laterally extending leading edge 726. The leading edge 726 can be formedby the PCB material itself or, preferably, by hardened material, such asa metal appliqué or band formed in a “U” or a “V” configuration engagingthe PCB 724 by upper and lower members 728 and 730 affixed to the upperand lower surfaces 732 and 734 of the PCB extension 722 such as bysoldering. The upper and lower members 730 and 732 can serve aselectrical ground pads. Upon installation of the PCB 724, the sharpleading edge 726 first contacts and cleaves the exposed wire screen 710into the form illustrated in FIG. 139.

In addition to the forgoing, punch dies 712/714 such as those depictedin FIG. 156 can be employed in modified form to actually sever and/orremove a portion (or all) of the wire screen 710 after the molding ofthe housing case 704, but before the final assembly of the audio system702. Furthermore, one or more service access windows can be providedelsewhere in the walls of the housing case 704. The service windows areclosed at the time of manufacture by exposed screen includingperforations. The exposed screen could be severed by a tool or processlater in the service life of the audio system 702 to service or modifythe system.

The method of grounding the plastic front plate (with molded in metalmesh) to the keyboard is by using plastic spring clip that contains anopen window to expose the mesh where the spring clip comes into contactwith a tinned pad on the keyboard. This provides an ESD path to groundwhen inserting a static charged CD into the CD changer.

Referring to FIGS. 8-11 and 21-22, several spring clip structures 228are integrally formed in the front plate 70 which, in assembly,continuously resiliently bear locally exposed segments of the wirescreen 212 against a tinned grounding pad 230 (only one is illustrated)on a keypad PCB 232 to establish a ground path therebetween.

Each spring clip structure 228 has a frame 234 including two parallelarc shaped portions 236 and 238 and a cross-support portion 240integrally formed with front plate 70 and extending therefrom as aresilient cantilever. An opening 242 in the front plate registers witheach spring clip 228 to permit flexure thereof.

Prior to molding of the wire screen 212 within the front plate 70 thescreen preform is die-cut to form an integral flap which is capturedwithin the mold and the edges thereof encased within arc-shaped portions236 and 238 and cross-support portion 240. The central portion of theexposed wire screen is expanded or stretched to form an outward bowshape (refer FIGS. 9 and 10) to ensure that the resulting exposed screenprotuberance firmly contacts the PCB grounding pad 230.

A prior approach is illustrated wherein separate spring grounding clips244 are each mechanically affixed to the front plate 246 of a radio/CDplayer assembly 248 by a rivet 250 or other suitable fastener. Therivets are required to establish an electrical ground path as well as tomechanically secure the spring clips 244 to the front plate 246, addinglabor, cost and complexity to the manufacturing process.

Using a plastic front plate enables assembly fixturing for the CDmechanism and circuit boards for slide lock and snap lock assemblyinstead of the screws used in a traditional receiver.

Referring to FIGS. 4 and 5, guideways in the form of slotted extensions126 and 128, as well as locator/retention features 144 and 146integrally formed on the reverse (inside) surface of the front plate 70provides a number of significant advantages in the manufacture and finalassembly of the radio/CD player 62 by reducing product part count,assembly time, and substantially eliminates dedicated hard fixturing andtools to affect assembly.

Using a plastic box for the receiver enables low cost location andsupport for the CD mechanism and enables for slide lock assembly insteadof the screws used in a traditional receiver. The brackets on the CDmechanism have a 1° taper that matches a 1° taper on the support shelfin the plastic box. This makes it easy for an operator to start theslide, but all of the clearances go to zero as the box snaps into placeproviding a strong rattle free assembly without the use of thetraditional screws.

Referring to FIGS. 12-18, 28, 29 and 32, the details of the mounting ofthe CD player subassembly 66 within the housing case 68 (refer FIG. 3)are illustrated in a simplified form. FIGS. 12-14 represent alongitudinal cross-section of a case guideway 370, including a rear wallportion 372 taken just laterally inside of the right side wall portion(not illustrated) of a housing case 374 to illustrate the spacialcooperation between the case guideway 370 and a right side CD playermounting bracket 376 during the insertion thereof in the assembly of aradio/CD player 378. A mirror-image case guideway is integrally formedon the opposite, left wall portion of the case 374.

The guideway 370 is integrally formed with the right sidewall portion(not illustrated) and the rear wall portion 372 of the housing case 374,projecting laterally therefrom. The guideway 370 is generally “C”shaped, having laterally disposed upper and lower leg portions 380 and382 extending longitudinally the entire depth of the case 374. The legportions 380 and 382 form continuously converging or tapered surfaces384 and 386, respectively, which are offset by an angle α (nominally 1°)vertically centered above and below a longitudinal assembly axis 388.The mounting bracket 376 is preferably stamped from sheet aluminum orsimilar material and is also generally “C” shaped, having a verticalportion 390 and laterally disposed upper and lower leg portions 392 and394 extending longitudinally substantially the entire depth of the case374. The leg portions 392 and 294 form continuously converging ortapered surfaces, respectively, which are offset by an angle φ(nominally 1°). The mounting bracket 376 has a leading edge surface 400which, upon assembly, approaches the inside surface 402 of the case rearwall portion 372. The vertical portion 390 of the mounting bracket 376has a rearwardly directed integral tab 404 extending from edge surface400. The tab 404 has a localized upset bead or rib 406.

The CD player subassembly is installed by manually aligning the leadingedge surface 400 of the mounting brackets 376 with the opening 408 ofthe guideway 370 (refer to FIG. 12) and rearwardly displacing it alongthe assembly axis 388. FIGS. 13 and 28 illustrate a mid-point in theinsertion process wherein the guideway surfaces 384 and 386 remainsubstantially parallel to the cooperating mounting bracket surfaces 396and 398. The guideway serves to register, align and guide the insertionof the mounting brackets 376. As the CD player subassembly 66 approachesthe installed position depicted in FIGS. 14 and 29, the guidewaysurfaces 384 and 386 contact the mounting bracket surfaces toeffectively provide a zero-tolerance interfit therebetween. This ensuresprecise positioning and effectively eliminates squeaks and rattles inapplication. As best viewed in FIGS. 14-18, in the installed position,the tabs 404 slip-fit penetrate into an opening or recess 410 in rearwall portion 372. The upset rib 408 forms an interference-fit within thewindow 410 to lockingly engage the CSD player subassembly 66 within thecase 374.

Referring to FIG. 30, an alternative mounting configuration of aninstalled CD player subassembly 412 within a housing case 414 isillustrated. A sidewall 416 of the case 414 integrally defines aguideway 417 which extends laterally outwardly to form facing acutelyoffset cooperating upper and lower guide surfaces 418 and 420,respectively. Likewise, the CD player subassembly 412 carries left andright mounting brackets 422 (only one is illustrated) having acutelyinwardly angled upper and lower legs 424 and 426, respectively, definingupper and lower surfaces 428 and 430, respectively.

Referring to FIG. 31, an additional alternative mounting configurationof an installed CD player subassembly 432 within a housing case 434 isillustrated. A sidewall 436 of the case 434 integrally defines aguideway 438 which extends laterally inwardly to form opposed acutelyoffset cooperating upper and lower guide surfaces 440 and 442,respectively. Likewise, the CD player subassembly 432 carries left andright mounting brackets 444 (only one is illustrated) having acutelyoutwardly angled upper and lower legs 446 and 448, respectively,defining upper and lower surfaces 450 and 452, respectively.

A localized area of wire screen 454 can be formed in the guideway 438 toaffect a ground path between the CD player subassembly 432 and the case434.

Referring to FIG. 31, an alternative guideway 456 for the CD playermounting bracket 376 (refer FIGS. 12-14) has upper and lower legportions 458 and 460, each having a tapered, increasing thickness in thevertical dimension along their longitudinal extent (along the assemblyaxis 462. Upper and lower guide surfaces 464 and 466, respectively, areoffset by angle α. Outer guideway edge surfaces 468 and 470 have aslight reverse taper at an offset angle ε (approximately 1°-3°) toprovide release draft for the injection molding process.

Molding in metal mesh into the plastic receiver case and front plateincreases the strength of the material (much like putting re-bar intoconcrete) while still weighing less than a steel case. The gauge of thewire forming the mesh can be increased and the amount of plasticmaterial can be substantially reduced, resulting in a very thin wall,robust structure.

As an alternative to the structure illustrated in FIG. 19, the plasticcan be eliminated from the center portions of some or all of theindividual side, front, back, top and/or bottom panel portions of thecase and front plate. This configuration would have the appearance of ascreen box, with a molded plastic peripheral frame circumscribing eachpanel portion.

Referring to FIG. 19, a lightweight automotive audio system 471 caninclude a housing case 472 constructed of a composite of polymer basedmaterial with a wire screen 474 insert molded therein to isolate audiocomponents therein from various electrical anomalies. To further reduceoverall weight, the gauge of the wire screen can be increased wherebythe screen contributes a significant component of the resulting overallstructural strength of the case, while the nominal section or thicknessof the polymer material can be substantially reduced. By way of example,the case 472 top and bottom wall portions 476 and 478, respectively, andleft and right side wall portions 480 and 482, respectively, injectionmolded into a single unified structure, with the enlarged gauge wirescreen 474 insert molded adjacent the inner surfaces thereof. Edges andcorners of the case 472 formed at the intersection of two or threeadjacent wall portions can be locally thickened to increase structuralrigidity of the case 472 as well as to provide internal and externalmounting and interface ports. The intersecting edges of the top wallportion 476 and the left and right side wall portions 480 and 482,respectively, form thickened left and right upper edge frames 484 and486, respectively. Likewise, the intersecting edges of the bottom wallportion 478 and the left and right side wall portions 480 and 482,respectively, form thickened left and right lower edge frames. Loweredge frames 488 and 490 are locally vertically extended openings 492 and494 for exposing the wire screen 474 to establish electrical contactwith contact clips 496 and 498 carried by PCBs 500 and 502,respectively, interconnected by pin connectors 504 within the case 472.

The example embodiment of FIG. 19 can be further modified to form anextremely lightweight case 506 constructed of polymer based material andwire screen 508. Case 506 is configured so that some or all of the wallportions comprise a polymer frame 510 about the perimeter thereof andthe wire screen 508 closing the center portion of such wall portions.Portions of the wire screen 508 adjacent edges of the case 506 areaffixed to the frame 510 such as by insert molding. Attachment featuressuch as mounting flanges 512, tab receiving extensions 514, rampedsnap-engagement features 516 can be molded as an integral portion of theframe 510. Ports, such as wiring harness interconnections 518 and 520,and coaxial cable antenna interconnections 522 can be easily moldedwithin an extended frame portion 524. Windows 526 and 528 can also beformed in extended frame portion 524 for electrically interconnectingthe wire screen 508 with internal components.

Using plastic for a receiver case enables low cost assembly of thecomponents. The circuit boards and the CD mechanism can slide into placeand then be locked or they can be snapped into place without screws.This reduces the number of parts required in the assembly and reducesthe amount of direct and indirect labor to put a receiver together. Theplastic case can be easily molded into a net shape forming the slidesand snaps needed for assembly.

Referring to FIGS. 2-5, the apparatus and assembly method describedsubstantially reduces the labor and component cost of the radio/CDplayer 62, as well as the required capital costs. Furthermore, itsubstantially enhances product quality by substantially eliminating thepossibility of extraneous or missing (small) parts and/or improperassembly.

Using the molded in metal mesh in the receiver plastic box that isgrounded to the circuit boards creates a Faraday cage that providesshielding protection for RFI (Radio Frequency Interference), EMI(Electro Magnetic Interference), BCI (Bulk Current Injection), and ESD(Electrostatic Discharge).

Referring to FIGS. 33-49, the electrically conductive material insertmolded within the polymer based material to form the case of anelectrical device is embossed through the formation of one or moreelongated upset beads within exposed regions (windows) of the case. Thisestablishes a localized resiliently displaceable portion of the case tofacilitate its fastenerless assembly and/or interaction with the hostvehicle. The exposed conductive material is, in assembly, in intimatecontact with subassemblies, such as a CD player mounting bracket withinthe case and establishes a robust electrical ground path therebetween.The upset bead ensures localized flexibility of portions of the case,preventing rupture of the conductive material and possible leakage ofelectrical anomalies.

Preferably, an extension of polymer based material forms a cantilevertab or island within the window which is resiliently displaceable duringthe assembly process. The tab forms a self engaging feature whichengages a mating projection extending from the mounting bracket of thesubassembly to retain the subassembly in its design intent location.

The embodiments of the invention described in connection with FIGS.33-49 correspond in most respects with the embodiments previouslydescribed in connection with FIGS. 12-18, 28, 29 and 32, with theexception of specifics set forth hereinbelow.

Referring to FIG. 33, an exploded, left-rear perspective view of alightweight electronic device 1850 configured for automotiveapplications is illustrated, including an electronic circuit componentsuch as a CD changer 1852 and a housing assembly 1854 featuringselectively embossed segments of exposed composite case electricalshielding material operative to enhance screwless assembly ofsubassembly brackets 1856 within (or exteriorly of) the case.Definitionally, subassembly brackets 1856 constitute adjacent structuralelements. As described hereinabove, the housing case 1854 is constructedas a composite of relatively rigid polymer based material andelectrically conductive material such as wire screen insert moldedtherein. Case walls including the electrically conductive materialsubstantially enclose and shield the electronic circuit component fromelectrical anomalies.

Opposed sidewalls 1858 form symmetrical guideways 1860 for receiving andguiding the brackets 1856 (and CD changer 1853) along assembly axes1861. Each bracket 1856 forms laterally diverging upper and lower legs1862 and 1866, respectively, which are separated by a vertical wallportion 1866. The brackets 1856 are formed of electrically conductivematerial which is in-circuit with the CD changer 1852. Each bracket 1856has an engagement feature or “bump” 1868 integrally formed therewithwhich extends laterally outwardly from the wall portion 1866 at a pointvertically intermediate the upper and lower legs, 1862 and 1864,respectively.

Each guideway 1860 forms laterally diverging upper and lower wallportions 1870 and 1872, respectively, interconnecting a vertical wallportion 1874 to its respective sidewall 1858. A window 1876 is formed invertical wall portion 1874 of guideway 1860, the window 1876 extendingentirely or substantially through the polymer material forming thesidewall 1858 and exposing a portion of wire screen 1878. A peninsularextension or tab 1880 is integrally formed with vertical wall portion1874 and extends as a cantilever into the window 1876. A recess oropening 1882 is formed adjacent the free end of the tab 1880. As bestviewed in FIG. 33, as thus constructed, the portion of the window 1876not closed by the tab 1880, i.e. that portion closed only by the wirescreen 1878, forms a general “C” configuration, with a base portion ofthe “C” disposed adjacent the free end of the cantilever tab 1880 andupper and lower parallel leg portions of the “C” extending continuouslyfrom the free end of the tab 1880 to its point of attachment with theadjacent vertical wall portion 1874 of the guideway 1860.

Referring to FIGS. 34 and 35, a broken, overhead sectional view of thecase 1854 and leading ends of the two brackets 1856 are illustrated withthe elements juxtaposed similarly to that of FIG. 171 wherein the CDcharger 1852 and its attendant brackets 1856 are aligned along theassembly axes 1861 prior to contact between the brackets 1856 and case1854.

Referring to FIGS. 36 and 37, as the two brackets 1856 (and CD changer1852) are inserted within the case 1854 along the assembly axes 1861,the bracket bumps 1868 initially slidingly contact their respectiveinner surfaces of vertical wall portions 1874 of guideways 1860.Advancement of the brackets 1856 along the assembly axes 1861 will causethe free ends of the brackets 1856 to resiliently deflect laterallyinwardly as depicted by arrow 1885.

Referring to FIGS. 38 and 39, as the two brackets further advance alongthe assembly axes 1861, the bracket bumps 1868 slide along the innersurface of each tab 1880, deflecting them outwardly. Simultaneously, theleading ends 1884 of the brackets 1856 register with and extendrearwardly outwardly through associated openings 1886 in the rear wall1888 of the case 1854 to laterally secure the leading end 1884 of thebrackets. When the leading ends 1884 of the brackets 1856 are engagedwithin their respective openings 1886, the overall structure of thebrackets 1856 is effectively stiffened and substantially preventingfurther inward lateral displacement as depicted by arrow 1885. Thus, theinterference fit of the bumps 1868 with the vertical wall portion 1874results in a maximum outward lateral displacement of the free ends ofthe tabs 1880. The leading ends 1884 of the brackets 1856 each have alocalized upset bead or rib that is dimensioned for interference fitwith openings 1886 to provide redundant interlocking engagement of thebracket 1856 with the back wall 1883 of the case 1854 similar to theembodiment of the invention described hereinabove in connection withFIGS. 12-18.

Referring to FIGS. 40-41, as the brackets 1856 (and CD changer 1852) arelongitudinally inserted into their design intent positions, the bumps1868 register with their respective openings 1882 within their tabs1880, resulting in the tabs 1880 resiliently relaxing and returning totheir original orientation with respect to the vertical wall portions1874 as depicted in FIGS. 34-37. Thus disposed, the rearwardly facingedge 1890 of each tab opening 1882 engages the forwardly facing edge1892 of the respective bump 1868 to releasably interlock the brackets1856 within the case 1854 without the use of separate components such asthreaded fasteners.

As best seen in FIG. 42, the electrically conductive wire screen 1878 isexposed at selected locations of the inner surface of the case sidewalls1858. In particular, the inner surfaces of the wall portions 1870, 1872and 1874 of the guideways 1860 expose the wire screen 1878 to ensureintimate contact with the brackets 1856 and thereby establish a reliableelectrically conductive path therebetween. Preferably, a section of wiremesh 1878 corresponding with the tab openings 1882, is removed to ensurefull penetration of the bracket bump 1868 within each opening 1882.

For the most part, the wire screen 1878 is formed in planer segmentscorresponding with the case walls. Portions of the wire screen 1878exposed within openings formed by the windows 1876 are embossed, meaningthat they have at least one laterally inwardly and/or outwardlyextending upset bead 1894 formed therein which is elongated to enablelocalized flexure of the wire screen 1878 during cantilever flexure ofthe tab 1880 during insertion of the brackets 1856. Preferably, the lineof elongation of the upset bead 1894 extends parallel to and spaced fromthe edges of the rigid polymer material delimiting the window openingand is disposed intermediate the window edges and the cantilever portionof the tab 1880. As best seen in FIG. 39, the upset bead 1894 ismomentarily distended during the final stages of insertion of thebrackets 1856 and, as best seen in FIG. 41, returns to its originalconfiguration upon completion of the assembly process. Referring toFIGS. 33, 41 and 42, the upset bead 1894, in this embodiment of theinvention, mimics the open wire screen 1878 configuration, extendingcontinuously vertically along the base of the “C” wire screenconfiguration and longitudinally forwardly along the entire length ofthe legs of the “C” wire screen configuration.

Although subject to variations depending upon specific designrequirements, the degree of upset of the bead 1894 is preferablyapproximately equal to the nominal thickness of the adjacent rigidpolymer based material.

Referring to FIGS. 43 and 44, an alternative design of the presentinvention is illustrated. A window 1896 formed in a wall 1898 of a case1900 exposing a segment of wire screen 1902. A discrete or “floating”island 1904 is insert molded with a central portion of the wire screen1902 but is spaced from the wall 1898. The wire screen 1902 is embossedwith three concentric continuous upset beads, an inner bead 1906, anouter bead 1908 and an intermediate bead 1910. The upset beads 1906,1908 and 1910 are spaced to function as a diaphragm for maximummomentary distension during the assembly process. The island 1904 has arecess 1912 formed in the inner surface thereof for engaging anelectronic circuit component (not illustrated). Each of the upset beads1906, 1908 and 1910 extend circumferentially continuously about theisland 1094 to effect substantially symmetrical distensioncharacteristics in both the “X” and “Y” axes designated by arrows 1914and 1916.

Referring to FIGS. 45 and 46, a second alternative design of the presentinvention is illustrated. A window 1918 formed in a wall 1920 of a case1922 exposing a segment of wire screen 1924. A discrete or “floating”island (not illustrated) such as that described in connection with theembodiment of FIGS. 43 and 44 can also be insert molded with a centralportion of the wire screen 1924 which is spaced from the wall 1920. Thewire screen 1924 is embossed with two concentric continuous upset beads,an inner bead 1926 and an outer bead 1928. The upset beads 1926 and 1928are spaced to function as a diaphragm for maximum momentary distensionduring the assembly process. Each of the upset beads 1926 and 1928extend circumferentially continuously, but are circumferentiallyirregular to affect asymmetrical distension characteristics in the “X”and “Y” axes designated by arrows 1930 and 1932, as well as to provide adecorative motif or distinguishing design.

Referring to FIGS. 47 and 48, a detailed exemplary solid model of a maledie portion 1934 of a die set configured to affect formation of thecomposite electronic device case 1854 of FIG. 33, illustrating thedetail of the region of the die portion 1934 which establishes the caseside window 1876 and affects formation of the conductive material upsetbead 1894 upon closure with a mating die portion (not illustrated). FIG.48 depicts an exemplary dimensioned profile of the male die portion 1934of FIG. 47 through its region which forms the case window 1876. Male dieportion 1934 has an external surface 1936 taken along section line 48-48of FIG. 47 defining details 1938 and 1940 for forming the inner surfaceof a case sidewall 1858, details 1942 and 1944 for forming opposed legsof the case window 1876, details 1946 and 1948 for forming opposedportions of the screen upset bead 1894, details 1950 and 1952 forforming the integral tab 1880 within the window 1876, and a detail 1954for forming the tab recess/opening 1882.

FIG. 49 depicts a Product Data Sheet of steel mesh employed by theapplicant in certain embodiments of the composite case of the presentinvention.

It is to be understood that the invention has been described withreference to specific embodiments and variations to provide the featuresand advantages previously described and that the embodiments aresusceptible of modification as will be apparent to those skilled in theart.

Furthermore, it is contemplated that many alternative, commoninexpensive materials can be employed to construct the basis constituentcomponents. Accordingly, the forgoing is not to be construed in alimiting sense.

The invention has been described in an illustrative manner, and it is tobe understood that the terminology, which has been used is intended tobe in the nature of words of description rather than of limitation.

Obviously, many modifications and variations of the present inventionare possible in light of the above teachings. For example, a number ofthe various radio/CD player case constructions illustrated herein areillustrated as being formed of solid molded polymer material for thesake of simplicity and clarity of understanding. It is to be understood,however, that the wire mesh depicted, for example in FIG. 20, can beemployed in the other configurations and embodiments with equal success.Furthermore, several of the housing assembly structures are describedherein as being formed of metal. However, a wide range of materialsubstitutes, including plastics, ceramics, non-ferrous metals andcomposites can be substituted without departing from the spirit andscope of the present invention. The terms “snap-engaging” and“self-engaging” are intended to interpreted very broadly inasmuch asinnumerable structural, process (e.g. weldments) and chemical (e.g.adhesives) equivalents are available. It is, therefore, to be understoodthat within the scope of the appended claims, wherein reference numeralsare merely for illustrative purposes and convenience and are not in anyway limiting, the invention, which is defined by the following claims asinterpreted according to the principles of patent law, including theDoctrine of Equivalents, may be practiced otherwise than is specificallydescribed.

What is claimed is:
 1. A self-positioning, self-engaging mounting systemfor an electronic circuit component within a lightweight electronicdevice comprising: a box-like case having integrally formed wallportions and a front opening disposed generally symmetrically about alongitudinally extending assembly axis, wherein a laterally opposed pairof inner wall surfaces each define a complimentary set of verticallyspaced, longitudinally converging guideways; and a pair of electroniccircuit component mounting brackets secured to laterally opposedsurfaces of said electronic circuit component and extendinglongitudinally a dimension less than or nearly equaling the longitudinaldepth of said case, wherein each said bracket defines a complimentaryset of vertically spaced, longitudinally converging guide members. 2.The mounting system of claim 1, wherein said case is formed of acomposite of relatively rigid polymer based material and electricallyconductive material insert molded within said polymer based material,said electrically conductive material operable to substantially encloseand to shield an electronic circuit component disposed within said casefrom electrical anomalies.
 3. The mounting system of claim 2, whereinsaid case includes at least one opening in one of said wall portionsintermediate an associated pair of vertically spaced guideways, saidopening closed by an embossed segment of said electrically conductivematerial.
 4. The mounting system of claim 3, further comprising asegment of rigid polymer based material resiliently carried within saidopening for limited lateral displacement with respect to said case. 5.The mounting system of claim 4, wherein said segment of polymer basedmaterial defines an engagement surface operative to fixedly engage acooperating feature of an adjacent mounting bracket.
 6. The mountingsystem of claim 5, wherein said embossed segment of electricallyconductive material is configured to bear continuously against anelectrically conductive portion of at least one of said electroniccircuit component mounting brackets to establish an electricalconnection therebetween.
 7. The mounting system of claim 1, wherein saidelectronic circuit component comprises an electronic circuit boardsubassembly.
 8. The mounting system of claim 1, wherein said electroniccircuit component comprises a CD changer.
 9. A method of forming ahousing case for a lightweight electronic device comprising the stepsof: preparing a die set which, when closed, defines the envelope of thehousing case; inserting electrically conductive sheet material, such aswire screen or mesh within the die set; filling the die set with moltenpolymer based material to form a composite structure with saidconductive material; and removing the hardened case from the die set.10. The method of claim 9, further comprising the step of forming awindow in said case, said window being devoid of said polymer basedmaterial and substantially closed by said electrically conductivematerial.
 11. The method of claim 10, further comprising the step ofembossing the exposed electrically conductive material within saidwindow.